Features Enter your model number to make sure this fits. Material: [shell] polyester ripstop, [lining] polyester Insulation: synthetic Shape: semi-mummy Zipper: [petite] 55-inch YKK #8, [regular] 65-inch YKK #8 Shoulder Circumference: [petite] 54 in, [regular] 56 in Description Product Description When the lake turns black, sneak into your tent and tuck yourself into the Big Agnes Blue Lake Sleeping Bag. Rated to 25-degrees Fahrenheit, the Blue Lake feels right in most conditions from spring to fall. Its synthetic insulation stays warm when wet, and keeps you nice and toasty in moist environments. A semi-mummy shape allows room for shifting and turning yet keeps the bag compact for camping convenience. Big Agnes designed this bag with a unique cordlock that lets you un-cinch the hood in warmer weather, There are internal loops for liners, and external loops for hanging the bag out to air. The Blue lake also features a mesh storage sack and a nylon stuff sack.